CB 3380-1991: Macro Etching Test Method for Marine Steel Weld Joints
Standard Overview
Standard Number: CB 3380-1991
Title: Macro Etching Test Method for Macrostructural Defects in Marine Steel Weld Joints
Industry: Marine Engineering / Shipbuilding
Status: Chinese Shipbuilding Industry Standard
Scope
This standard specifies the macro etching test method for examining macrostructural defects in welded joints of marine steel structures. The method is used to reveal defects such as:
- Incomplete penetration
- Cracks and fissures
- Porosity and gas pockets
- Slag inclusions
- Weld bead profile irregularities
- Heat-affected zone characteristics
Test Principle
The macro etching test involves cutting a cross-section of the weld joint, polishing the surface, and then etching it with an appropriate chemical reagent to reveal the macrostructure. The etched surface is then visually examined or photographed for defect analysis.
Key Test Parameters
| Parameter | Specification |
|---|---|
| Sample Preparation | Cross-section perpendicular to weld direction |
| Surface Finish | Polished to mirror finish before etching |
| Etching Reagent | Acid solution (typically 4% Nital or similar) |
| Etching Time | As specified in standard procedure |
| Examination Method | Visual inspection with magnification (5-10x) |
Applications
This test method is widely used in:
- Ship hull construction quality control
- Marine pipeline weld inspection
- Offshore structure fabrication
- Welding procedure qualification
- Failure analysis of welded components
Download Original Standard
📄 Original PDF Document (Chinese)
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Related Standards
- GB/T 2653-2008: Welding joint tensile test
- GB/T 2654-2008: Welding joint hardness test
- CB/T 3558-2005: Radiographic inspection of ship steel welds
Published: 2026-05-08
Category: Marine Engineering Standards / Quality Control
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